The present invention relates generally to a method and apparatus for displaying operational information in a control system. Operational information is displayed using a starfield display as a metaphoric abstraction of system operation. In a particular embodiment of the invention, information pertaining to the operation of a facility management system is abstracted and displayed in a starfield display.
Control systems generally include one or more sensors, an operational unit and a controller. The sensors detect a condition, such as a temperature, a pressure, humidity, or an operational status, such as on or off, air velocity, etc. The operational unit includes equipment, such as a heater or chiller or a pump, capable of changing the detected condition. The controller receives a signal from the sensors and provides a control signal to the operational unit to control the operational unit. Commonly, in a negative feedback loop, the operational unit is operated to maintain the condition at a predetermined setpoint or within a predetermined range. The controller determines a difference between the signal from the sensor and the setpoint and controls the operational unit to reduce or eliminate the difference to obtain the desired setting for the condition.
One example of a control system is a facility management system. Such systems control a building""s heating, ventilating, air conditioning, lighting, security and fire systems. Conditions such as temperature and humidity are detected by sensors such as temperature and humidity sensors. These conditions are controlled using operational units such as chillers, boilers and fans. Such facility management systems may include 400,000 or more sensed and controlled parameters. Operation of such a system is under the control of a process manager or the researcher.
Complex systems, such as facility management systems, can generate substantial quantities of data that could easily overwhelm a process manager. A process manager, monitoring such a complex system needs to identify potential or actual operational problems in the system and respond to solve the problems in a timely manner. Also, during research and simulation of complex systems, the researcher needs to identify similar potential or actual problems. To do this, operational information must be displayed in a manner which is clearly understood and utilized by the process manager.
Graphic interfaces developed for displaying control information in facility management systems are illustrative of prior art methods and devices for displaying operational information in complex control systems. In the 1960""s, process control and facility management systems used mimic panels located throughout a facility. These mimic panels consisted of dials, gauges, valves and switches mounted on large panels painted with electrical, plumbing, process or HVAC (heating, ventilation and air conditioning) duct diagrams. System operation was monitored by touring the plant and monitoring the individual panels.
In the early 1970""s, these hard-wired panels were replaced with centrally located minicomputers and text display cathode ray tubes (CRTs). This allowed for a concentration of sensor data and thus savings in time for personnel who no longer had to walk around the plant or buildings, recording and checking system data panels. To present relationships between the data and the elements of the monitored system, projectors would display slides of the pictures which were formerly on the mimic panels. Thus, a single sensor, single indicator (SSSI) paradigm was maintained. The static signal which represented function or location was displayed on the slide with the assigned name while the name and the current value was on the CRT. The operator was expected to view the projector and the display to determine the relationship between the sensor""s function or location and its value.
Color CRTs were introduced in the late 1970""s, but these merely replaced the slide projector with dynamic values overlaying the static picture. This made the display two levels deep: a static portion or background level, representing functional or locational references, and a dynamic portion or foreground level displaying the current sensor values. As technology improved, changes were made to the dynamic portion of the display. Color was added to indicate the status of the sensor (alarm or normal) or a switch state (on or off). Analog values were represented with a bar graph element which showed relative values with respect to an upper bound and a lower bound. Limits were also added so the operator could determine how closely a monitored condition was maintained to a setpoint. The equipment signals were moved to the dynamic portion and were also color-coded. For example, a pump symbol was coded green if on and red if off. Flashing symbols added another level of information. Multiple symbols were alternated on the display to give the illusion of animation. Direct manipulation techniques were added, allowing the operator to xe2x80x9cclick onxe2x80x9d the fan symbol to change its state or to xe2x80x9cclick and dragxe2x80x9d the setpoint indicator on an analog bar graph to change the setpoint value. Other techniques were added to allow penetration beyond the display to detailed graphics or text views. All of these techniques improved the effectiveness of the displayed information, allowed more sensors to be monitored and reduced some of the cognitive load on the operator. The paradigm remained that of a single sensor, single indicator.
However, in modern, complex control systems, the number of sensed and controlled parameters has continued to grow. Some complex systems may have 400,000 such parameters, and future systems will certainly have even more. Prior art display systems will not enable a process manager to effectively monitor large numbers of parameters. Moreover, prior art techniques are still tied to the location and function diagrams of the physical system. To move beyond these diagrams, and to allow the system to accommodate even greater levels of complexity, it is necessary to provide an abstract representation of the physical data.
An abstract representation of the data would allow the data and relationships among the data points to be more effectively presented. By observing visual attributes in an abstracted display, as well as patterns and changes in the display, an operator could monitor a greater amount of data. The operator could also determine relationships between operational parameters of individual components of the control system. Through experience with starfield displays produced in response to a variety of conditions, the operator could readily identify operational problems before they occur and act to correct potential problems.
The present invention provides a control system comprising a plurality of sensors producing a plurality of sensor signals. Each respective sensor produces a respective sensor signal in response to a respective sensed condition. The control system further comprises a plurality of controllers producing a plurality of control signals in response to one or more of the sensor signals, each respective controller producing at least one control signal. The control system further comprises a plurality of operational units, each respective operational unit being connected to a respective controller for receiving one or more control signals, each respective operational unit producing a control effect in response to one or more control signals. Still further, the control system comprises a display device connected to the plurality of sensors and the plurality of controllers and producing a starfield display in response to the plurality of sensor signals and the plurality of control signals.
The invention further provides a method for providing operational information in a facility management system, the facility management system including a plurality of functional units, a controller, and a display device. The method comprises the steps of receiving from at least one functional unit a sensor signal representative of the sensed condition and producing a starfield display on the display device in response to the sensor signal.
The invention still further provides a facility management system including one or more sensors responsive to an environmental condition and configured to produce a sensor signal, one or more fans responsive to a control signal configured to change the environmental condition, and a controller configured to be coupled to the one or more sensors and the one or more fans, the controller configured to generate the control signal in response to the sensor signal. The facility management system further includes a display device configured to be coupled to the one or more sensors and to the controller, the display device configured to produce a starfield display in response to the sensor signal and the control signal.